Here are some ideas:
Swet Cape:
Used to be in the voteshop long ago, and it could be cool to have back. Costs around 20 VP.
Enchanted Healing Stone
I found this in game once (not sure if it still there or not), and it gives the same effects as a golden apple. Costs around 15 VP.
Obsidian Sword
I have been wanting this for a while now. It is an unobtainable sword acting similar to the ice blade and phoenix sword. Costs around 50 VP.
Cactus Fruit
Unobtainable fruit. Costs around 15-25 VP for 4.
Pineapple
Unobtainable fruit. Costs around 10-20 VP for 4.
Camera
Takes screenshots. Costs around 10-20 VP.
Iron Boat 
Saw this on the wiki with no page. Not sure if it is in game. if it was, it would be cool if it could drive on lava. Costs around 10-15 VP.
Ore Seeds 
Unique item I thought of. Can be planted on stone, netherrack, end stone, or holystone (or maybe something more rare, like igneous rock). It will take time to grow, and when it finishes, it will give a random ore item (like coal or diamond). Of course rarer ores like diamond would be more rare, and maybe, if possible, it could drop nuggets rather than the full item (to make it less OP). This doesn't have to be in the voteshop, it could be somewhere else. If it was, it would cost 50-75 VP. This is just an idea, and it may be way to op to get added.